I didn't prepare for the PSB exam. You really can't prepare for it. It's very basic math, spatial reasoning, spelling, reading, etc. The only kicker is that it is timed. Be weary.
I have not worked in any medical field before, but have watched HOURS of reality trauma shows and health shows since I was a wee one. Having a vested interest doesn't hurt the subject matter absoprtion. :)
You can max out the PSB at 6 points. You can accumulate up to 16 points for admission. Most get in with 15s, but 16's exist and some 14's get in. RARELY will a 13 pull it off. I am sure they haven't admitted a 13 in quite some time... Plan on taking the PSB after you have taken your core classes. It does help. If you have maxed out points in other areas, you have to have a 14 to even be considered now. Shoot for a 5 on the PSB....